Our overall goals are to develop new optogenetic tools, which sensitize to light the activity of signaling proteins and the cells in which they are expressed. We will employ these remote controls for basic research into understanding and manipulating the mast cell secretion in response to antigens and allergens (which trigger the inflammatory response), fluid absorption across the retinal pigment epithelium (which plays a role in cystoid macular edema), as well as efforts to re-engineer neurons for cell replacement therapy for models of CNS neurodegeneration. We have already made significant progress in two other directions, which represent our major preclinical work, namely efforts toward: a) the treatment of pain and the analysis of pain circuits, and b) the restoration of vision in retinal pathologies that lead to loss of photoreceptors and blindness. Our approach is to develop molecularly focused methods for dynamic manipulation of specific proteins in the complex environment of cells, which can be used in intact tissues, and, indeed, in the live animal. The logic is to use light as both input and output to probe and control protein function in cells. While there has been significant progress in optical detection of protein function over the last 2 decades, remote control has become only possible recently, partly from the efforts of our NDC. The NDC for the Optical Control of Biological Function has spent the first funding period developing methods for using light to rapidly switch on and off the function of select proteins in cells. We have demonstrated that the strategies are broadly applicable across protein classes, including ion channels, G-protein coupled receptors and enzymes: three of the largest families of signaling proteins in cells and major drug targets for the development of new pharmaceuticals.